Fluid cooled wall construction and method of assembling the same



Nov. 9, 1943. n. L. GoDsHALK 2,333,777

FLUID cooLEn wm. cousnuowrou AND ramon oF Assnumne THE SAME F1104 nec. s1, 1941 s sheets-sheet 1 Fig-2 INV ENT OR.

j Rasse/Il. Gods/Ya/k ATTORNEY Nov. 9, 1943. R. l.. GoDsHALK FLUID COOLED WALL CONSTRUCTION AND METHOD ASSEMBLING THE SAME Filed Dec. :51, 1941 3 sheets-sheet 2 INVENTOR. BY @Lisse/ l. gods/m5( ATTORNEY Nov. 9, 1943 R. L. GoDsHALK FLUID COOLED WALL CONSTRUCTION AND METHOD OF AssEMBLTNG THE SAME I 3 Sheets-Sheet 3 Filed Dec. 31, 1941 INV ENT OR.

@d5/idk TTORNEY Patented Nov. 9, 1943 FLUID COQLED WALL CONSTRUCTION AND y METHOD 0F ASSEMBLING THE SAME Russell L. Godshalk, Akron, Ohio, assignor to The Babcock & Wilcox Company, Newark, N. J., a corporation of New Jersey Y Application December 31, 1941, Serial No. 425,044

6 Claims.

' 'This invention relates to heat exchange apparatus and more particularly to the type used for cooling the walls of fuel-fired furnaces and consistirig of a row of fluid heating tubes having their ends' connected to suitable inlet and outlet headers; n

Where a row of these tubes together with suitable intertube closures as,for example, studs and refractory, and the outer enclosure of insulation and the like, are assembled to form a vertical furnace wall, the tubes and wall are subcontraction and to outward thrust resulting from changes in furnace pressure and thermal expansion of associated walls and partitions. The inhei-ent rigidity of the tubes and wall is therefore augmented by vertical and lateral supports arranged to hold the wall parts in the desired assembled position and prevent warping or buckling of the tubes while permitting thermal expansion and contraction thereof in the plane of the wall.

Heretofore in Wall constructions of the character described, the tubes have been connected to common tie bars spaced along their length in a manner permitting the removal or replacement of any given tube when disconnected from its headers without disturbing other tubes in the wall assembly. The tie bars in turn, are supported on suitably located horizontal buckstay members which permit lateral and vertical movementsv of the tubes and wall in the plane of the wallpdue to temperature changes. The buckstays are mounted on vertical steel supporting members. For its connections to the tie bars each tube has metal plates or pads welded to the tube in the shop at spaced points along its length and connected to the tie bars in the field at the time of erection.

This construction frequently causes considerable trouble when the tubes and other wall parts are assembled in the field, due sometimes to the fact that the support members are not of the proper shape and dimensions and, therefore, are out of alignment with the rows .of pads welded to the tubes, and at other times to the fact that the pads on the tubes are not in alignment with the corresponding tie bars. `This latter condition usually results from improper location of the pads on the tubes when welded in the shop, or from the operation of expanding the tubes into the headers where a slight longitudinal displacement of a. tube may be required in order to obtain a good pressure-tight expanded joint beWeen the tube and the header. Any of these errors preject in operation to longitudinal expansion .and

vents quick and accurate assembly of` the wall parts and as the errors must be corrected in the iield, erection costs are considerably increased.

The main object of this invention is to provide a method of assembling a wall structure of the type set forth which eliminates the need for costly corrections or the like in the field, yet without any sacrifice in tolerance or workmanship and without increasing the number of operations .previously required to erect an installation having perfectly formed and located parts.

A further object is to provide an improved construction of the parts employed in connecting each tie bar to a. supporting buckstay to permit thermal expansion and contraction of the tubes, tie-bars and other wall parts.

These and other objects which will be apparentV to those skilled in the art are accomplished by this invention, embodiments of which are illustrated in the accompanying drawings, in which,

Fig. 1 is a vertical sectional view through part of a steam generating unit `having uid cooled walls constructed and assembled in accordance with the invention;

Fig. 2 is a section through a top-supported side wall of the unit shown in Fig. 1, taken on the line 2-2 of Fig. 1, some of the parts being omitted for clarity;

Fig. 3 is a horizontal section taken on the line 3-3 of Fis. 2;

Fig. 4 is a similar view on an enlarged scale showing the invention as applied to a portion of the wall having studded'tubes;

Fig. 5 is a transverse section on the line 5-5 of Fig. 4; f

Fig. 6 is a section on the line 6-6 of Fig. 5 with parts omitted, showing the tie bar and tubes in elevation;

Fig. 7 is a plan view ofthe stay assembly in position before the connection thereto of a row of closely spaced bare tubes;

Fig.r 8 Ais a view similar to Fig. 7 showing a further step inthe assembly operation;

Fig. 9 is a vertical section taken on the line 9-9 of Fig. 8; and

Fig. 10 is a perspective view showing the welding of the tubes to the pads and plates.

As illustrated, the invention is shown in connection with a steam generating unit 20 having a pulverized fuel burner 2l directed downwardly into a uid cooled furnace chamber 22, and a screened opening 23 leading to a fluid cooled gas passage 24, although it will be apparent that various features of the invention can be employed in a wide variety of installations,

tie bar and buck- `As illustrated. a row of vertical water tubes 2l lining the side walls of the furnace and open pass 24 are expanded into upper and lower headers 26 and 21. respectively, the unit as a whole beingk top-supported so that on thermal expansion, the lower ends of the tubes will be relatively free to move downwardly. When assembled each tube welded to one or more metal plates or pads 23 which are removably secured to horizontal tie bars 29 by any suitable means such, for example, as cap screws 3l. At regular intervals along each tie bar a pad is supplanted by a spacer lug plate 32 having outwardly extending parallel spacer lugs'33 welded thereon, each plate being welded to an associated tube and secured to the tie bar 23 in the same manner as the pads 2B.

A horizontally disposed steel member or buckv stay 34, shown in the drawings as formed by a channel 35 and I-beam 36, as shown in Fig. 5, extends along the side wall adjacent 'each tie bar. As illustrated in Fig. 3, each buckstay member is supported at one end on a vertical corner member 33l and at its opposite end adjacent the center of the corresponding wall on a vertical member 35'. The corner members 3l' are top-supported and carry only the vertical load of the buckstays them in the plane of the furnace wall as a result of the expansion and contraction of the tubes and furnace wall while preventing relative movement in a plane perpendicular to the wall. As shown, a series of clips inthe form of horizontal angles 31 are welded or otherwise secured to the buckstay opposite each pair of lugs 33, and each clip has a horizontal flange 38 provided with a slot 39 extending parallel to thev buckstay and tie bar. As shown in Fig. 3, at a predetermined position along the wall one of the clips has a round rivet hole 43 in its horizontal flange so that horizontal expansion of the wall in its own plane may take place in opposite directions from this point and the slots 39 are arranged accordingly. A rivet 33 extending through holes in each pair of lugs 33 and the corresponding slot 33 removably connects each spacer plate 32 and tie bar 29 to the buckstay while permitting relative movement therebetween in directions parallel to the plane of the wall.

In erecting installations of this type in accordance with the present invention, the pads 23 are not welded to the wall tubes in the shop as heretofore but, on the contrary, are secured in place on the tie bars by the cap screws 3l in the shop before the tie bars are shipped. The lug plates 32 are similarly secured on the tie bar at that time.

In erecting a furnace wall in accordance with this invention. the structural steel members 34' and l35' and the buckstays 34 are rst put in place. The horizontal tie bar assemblies, shipped with the pads 23 and lug plates 32 bolted on the tie bars, are then mounted in position on the buckstays by inserting temporary erection bolts through thevslots 33 vin the clip flanges 3a and the holes in one of each pair of spacer lugs 33. When the wall is top-supported as described, the

parte are arranged with each clip flange 3l above and bolted to the lower lug 33 to permit relative downward but not upward movement of the tubes. Each tie bar is secured rigidly in place by this means so that the inner faces of the associated pads 2l and lug plates 32 will lie in a plane tangent to the outer faces of the wall tubes when the latter are subsequently installed. 'I'he tubes are then located in properly spaced position and expanded into the header tube holes in the usual way to produce pressure-tight connections. Thev tubes are then clamped tightly against the faces of the pads 23 and the plates 32 by any suitable means such, for example, as the strong back and tube spacer 3| and hook clamps 42, as

illustrated invFigs. 8 and 9. When so clamped the tubes are integrally secured to the pads 2l and the platesv 32 by welding as, for example, the deposit of weld metal at the upper and lower edges thereof, as shown in Fig. 10. after which the strong back and clamps are removed. The temporary bolts connecting the spacer lugs 33 and the clip angles 33 are then removed and the rivets 43 and associated washers and cotterl pins are substituted' permitting horizontal and downward expansion of the tubes and wall in the plane of the wall to an extent limited onlyby the eective lengths of the slots 33 and rivets 43, the horizontal expansion being in opposite directions from the center hole I3 shown in Fig. 3.

thus be expanded into the headers without regard yto pad alignment.

As indicated in Fig. 4, the spaces between the tubes are usually filled with plastic refractory 44 which is applied after the tubes` are in place. I'he usual block insulation Il, is also provided, as well as an outer metal casing 43.

When the buckstays are fixed in position so that no outward movement of the tubes andwall is permitted, the necessary alignment of the pads 23 and lug plates 32 is secured by bolting the vertical flanges of the clip angles to the channel section of each buckstay and using shims there between as needed.

It will be apparent that the invention can be variously modified and adapted within the scope of the appended claims.

Iclaim: Y

1. The method of field assembling a wall having a row of vertical tubes extending between headers and connected to an intermediate transverse tie bar, which comprises installing the tie bar with tube-contacting pads mounted thereon n 'v at points spaced along the length thereof, installing said tubes in said headers with one side f thereof in contact with said pads, and then rigidhaving a row of vertical fluid cooled tubes along' the furnace side,l thereof and connected to transverse headers, which comprises securing a series of tube-contacting pads at points spaced along the length of a common tie bar, installing said tie bar intermediate said headers and with one face of said pads in position to properly locate said tubes when in contact therewith, installing said wall tubes in said headers, and then rigidly securing said tubes to said pads.

3. The method of assembling a furnace wall having tubes supported between headers on transverse tie bars. which comprises removably securing a series of tube-engaging pads in predetermined spaced relation along a tie bar, installingsaid tie bar with the faces of said pads in a plane tangent to the outer faces of said tubes when in loperative position, installing said tubes in said headers at a spacing corresponding to the spacing of said pads along said tie bar. holding said tubes in contact with said pads, and then welding said tubes to said pads.

4. The methodof assembling a furnace wall having a row of vertical tubes along the furnace A side thereof andconnected totransverse headers, which comprises removably securing a series l of tube-contacting pads and spacer lug plates in predetermined spaced relation along a common tie bar, mounting said tie bar horizontally on a supporting buckstay bymeans of a. temporary rigid connection and with one side of said pads and plates in a vertical plane tangent to the outer sides of said tubes when 'in operative position, installing said wall tubes in said headers at a spacing corresponding to the spacing of said pads and plates along said tie bar, holding said tubes in contactwith said-padskand plates, then welding said tubes to said pads andfpl-ates. and

connectingv said tie `bar and buckstay to permit relative movement of said 'tubes in the plane of said wall.

5. The combination in. a furnace wall having a row of parallel fluid cooled tubes, of a transverse tie bar, tube-contacting pads mounted on said tie bar and secured to said tubes, a lug plate mounted on one of said tubes and secured to said bar, a spacer lug mounted on and extending outward-l ly from said plate, a.v supporting buckstay, and means for connecting said lug to said buckstay to permit relative vertical and horizontal movement therebetween including a slotted flange mounted on said buckstay and positioned'adjacent said lug, and a pin extending through said lug and the slot of said flange.

6.'The combination in a furnace wall having a row oi' top=supported vertical iluid cooled tubes, of a horizontal tie bar, tube-contacting pads mounted on said bar and secured to said tubes.

parallel lugs mounted on and extending outwardly from said tieLbar, a supporting buckstay, and means connecting said lugs to said buckstay to permit downward and horizontal movements of said tubes relative to said buckstay including a slotted flange horizontally mounted on said buckstay and positioned' between said lugs. and a vertical pin extending through said lugs and the slot of said ilange.

RUSSELL L. GODSHALK. 

